Rearrangement of allylic azide and phenylthio groups of 3′-azido- or 3′-phenylthio-4′,5′-didehydro-5′-deoxyarabinofuranosyluridines

The reversible intramolecular [3,3]-sigmatropic rearrangement between 1-(3-azido-3,5-dideoxy-β-d-threo-pent-4-enofuranosyl)uracil () and 1-(5-azido-3,5-dideoxy-β-d-glycero-pent-4-enofuranosyl)uracil () and irreversible radical rearrangement of 1-(3,5-dideoxy-3-phenylthio-β-d-threo-pent-4-enofuranosyl)uracil () and 1-[3,5-dideoxy-3-(4-tolyl)thio-β-d-threo-pent-4-enofuranosyl]uracil () into 1-(3,5-dideoxy-5-phenylthio-β-l-glycero-pent-4-enofuranosyl)uracil () and 1-[3,5-dideoxy-5-(4-tolyl)thio-β-l-glycero-pent-3-enofuranosyl]uracil () were attained at room temperature.